first, you make your sim have a very good relationship, such as being able to make out and goose each other (kind of flirt) plus you should try making them best friends. then make two sims relax on a...
it should be the same as on computer. get the two sims you want to have a baby (but make sure they get along very well) to relax on a double bed and make sure one of the people in bed have the green...